Generally, wireless enabled devices have to pass a variety of industry and regulatory certifications before they can be put on the marked. The certifications include regulatory/compliance testing, such as EMC testing, conformance testing (such as protocol, RF, RRM or LBS), as well as performance testing (such as over the air (OTA) measurements). OTA measurements are specifically performed to measure antenna patterns and include the measurement of the total radiated power (TRP) of a device under test at incremental locations surrounding the device. Other OTA measurements are total isotropic sensitivity (TIS), effective isotropic radiated power (EIRP) and effective isotropic sensitivity (EIS) measurements.
Application Note R&S TS8991 of Rohde & Schwarz, with the title “OTA Performance Test System, Single-source turnkey solutions for cellular and non-cellular wireless testing,” relates to an OTA performance test system to analyze and optimize radiated device performance and to validate conformance with industry, network operator and internal company requirements. The document describes the measurement of the TRP, which is a figure of merit for the transmitter performance of a DUT. According to R&S TS8991, the radiation pattern of a device under test is generally measured every 15° in both azimuth and elevation using a measurement antenna. At each position, the EIRP is measured and the TRP corresponds to a spatial average of the EIRP values taken uniformly around the DUT. Alternatively, in addition to the measurement every 15′ in both azimuth and elevation, TS8991 discloses a spiral scan approach to perform TRP measurements significantly faster with no loss in accuracy.
Even though TS8991 describes the spiral scan to perform TRP measurements faster, TS8991 is lacks a disclosure of the adjustment of the measurement grid during the measurement to reduce measurement time. Further, TS8991 does not describe any correlation between the grid configuration and at least one parameter of a measured value or data about the DUT. Thus, this document does not disclose an adjustment of the measurement grid in dependence of input data, which allows to decrease test time for OTA measurements while keeping the measurement uncertainty in a reasonable region. Taking into account additional input data, allows to reduce the number of measurement points and thus, to decrease test time, without reducing test accuracy.
What is needed, therefore, is an approach for performance testing of a device under test (DUT) that facilitates the adjustment of the measurement grid based on at least one parameter of at least one measured value or data regarding the DUT.